The necessity for providing drinking water to animals cannot be understated. Animals must have water in order to survive and to assist in converting solid feed into usable products for providing metabolizable energy to the animal.
In farming situations, water is generally fed to animals in the out-of-doors or in an open-air building, such as a livestock pavillion or a barn. When the air temperature is below freezing, the water in this environment will eventually freeze, preventing access to the water. To enable an animal in this situation to have water, the prior practice has been to break the ice cap on the surface of the water in order to gain access. Generally, the animal will nudge its nose against the ice to break it. Unfortunately, this practice must be maintained at a regular interval in order to prevent the ice cap from becoming too thick. In such situations, the animal will not be able to break the ice without, assistance. This requires the time of a person to constantly monitor drinking vessels during subfreezing temperatures.
In order to solve this dilemma, it has been the practice to provide an electrically heated container, which will maintain the water at above-freezing temperatures. Examples of such drinking vessels are as follows:
U.S. Pat. No. 1,033,799 to Harvey is directed to an electric water heater, which comprises an outside base member and an inside vessel. Situated within the vessel is a high-resistance heating coil enclosed in insulation. Additionally, there is a circuit breaker to maintain the temperature of the water.
U.S. Pat. No. 2,665,366 to Cleveland is directed to an open vat, which is electrically heated to provide water for animals. A continuous length of heating wire is passed around the bottom of the vat over positioned rods in order to form a series of closely arranged loops. The heating wires keep the contents of the vat thawed.
U.S. Pat. No. 3,648,659 to Jones is directed to an electrically heated bird bath, in which a heating unit is mounted in a recess next to bowl of the bird bath.
U.S Pat. No. 3,820,508 to Robinson is directed to a portable drinking bucket, specifically intended for a horse. The bucket contains an inner container and an outer container. An electric heating means is disposed between the inner and outer container. Insulation is provided around the heating means.
U.S. Pat. No. 4,640,226 to Liff is directed to a water apparatus containing spaced inner and outer walls. Situated between the walls is an electric heating means to keep the water device from thawing. The electric heating wires are coated with an insulation material.
U.S. Pat. No. 4,320,721 to Silcox is directed to an animal watering apparatus which includes an inner and outer wall, between which is placed an electric heating element. The electric heating element is disposed between insulation.
The Dunn's 1988 Catalog, page 79, is directed to a heated water bucket, which is disclosed as maintaining automatic temperature control. The inner bucket is stainless steel.
It has been found that many of these containers suffer from a variety of disadvantages. For example, the containers may be too large to allow easy portability. Therefore, the drinking vessel must be "permanently" placed at one location. This has the disadvantage of not allowing easy portability of drinking water to animals which may remain in sub-freezing temperatures, but out of the range of a drinking vessel. In order to compensate for this, a person must then bring the animal to the drinking water.
An additional deficiency is that many of the drinking containers of the prior art have exposed heating elements, which may either cause burns or electrical shock to the animal. Should this occur, the animal may become frightened of the vessel and refuse to go near it thus defeating the entire purpose of the apparatus.
In addition, many of the prior art heating vessels are equipped with insulation, generally in the form of fiberglass insulation, which is packed around the heating elements. Examples of such prior art heating vessels are disclosed in U.S. Pat. Nos. 1,033,799 to Harvey; 3,820,508 to Robinson; 4,640,226 to Liff; and 4,320,721 to Silcox, all of which have been previously described. Although insulation may have been described as having heat beneficial qualities, the inventor has discovered that packed insulation can be detrimental to a heated water container. The heating of the elements causes water in the air to condense on the insulation. In subfreezing weather, the condensed water on the regions of the fiberglass farthest from the heating elements will freeze. The freezing effect will cool the water container thus requiring more heat energy output from the heating elements.